Solid and liquid waste utilization in fermentation process to get bacterial insecticide.

Proceeding of the 5th International Congress on Engineering and Food, 28 May and 3 June, 1989, Cologne, Federal Republic of Germany

Recent observations on bacterial insecticide production by semi-solid fermentation technique.

The practical use of entomopathogenic microorganism, to crop protection is possible when an industrial scale production of the organism is developed. That is the case of Bacillus thuringiensis (Bt), one of the most studied and commercially important entomopathogenic bacterium. In Brazil the feasibility of Bt production depends, to a large degree, on the cost at which this product can be obtained. So, the fermentation technology has to aim the production of new fermentation media and new fermentation processes to get such economical level. In search of new fermentation processes it was studied the production of Bt spores and gama-endotoxin in a low cost medium (using agroindustrial by-products) by the semi-solid fermentation in flasks. The fermented malt and the solid residues from pulp and paper industry could both be used as a complete medium for growth and sporulation of this bacterium. Furthermore, the humidification or the supplementation of the culture media with a low price mineral salt source increases the yield of the spores production. It was concluded that the semi-solid fermentation technique can be successfully used for Bt spores and gama-endotoxin production

Outlook on the use of semi-solid culture media for the production of Bacillus thuringiensis.

Based on the fact that wider use of Bacillus thuringiensis for the biological control of insect pests has been restricted by economic reasons, studies were initiated to explore the feasibility of producing Bt. endotoxin preparations using semi-solid fermentation with cheap components as substracts. Some agroindustrial by-products including solid residue from paper industry, residual fermented malt from beer industry, and a special kind of meal obtained from residual cookies and biscuits of bakery industry, were investigated for their abilities to support Bt. growth and spore production. The technique was based upon the employment of semi-solid type of fermentation in erlenmeyers whose culture medium was composed by each residue separated, or by the combinatio n of two residues. The incubations was done at 30. C., with one hand-shaking each day, and spore counts and pH measurement were done until the seventh day. The semi-solid process used takes nearly 168 hours to produce 10 10 - 10 13 spores/g. The submerged fermentation results are nearly 10 9 - 19 10 spores/ml, in about 48-71 hours. Economic studies are conducted to determine the advantageous process, but the low cost of residues, the availability of them in Brazil, the technological aspects of production in small scale in some regions of the country, seem to be sufficient reasons to adopt the semi-solid fermentation process for Bacillus thuringiensisi production

Fungos associados a sementes de açaí: efeito da temperatura e do teor de água das sementes durante o armazenamento.

O trabalho teve como objetivo verificar os efeitos do teor de água e da temperatura do ambiente de armazenamento na incidência de fungos e na germinação de sementes de açaí (Euterpe oleracea Mart.). Foram utilizadas sementes da cultivar BRS Pará, com teores de água de 43%, 37%, 30%, 26%, 21% e 12%, que foram acondicionadas em sacos de polietileno, armazenadas sob temperaturas de 20 ºC, 15 ºC e 10 ºC, durante 360 dias e submetidas a avaliações bimensais do teor de água, da germinação e da incidência de Penicillium sp., Aspergillus sp., Fusarium solani e Fusarium verticillioides. Foi adotado o delineamento experimental inteiramente casualizado com quatro repetições para o teste de germinação e cinco repetições para os testes de sanidade. Foi observada maior ocorrência de Penicillium sp., e Aspergillus sp em sementes com teores de água abaixo de 30% e mantidas nas temperaturas de 15 ºC e 20 ºC. Enquanto, as maiores incidências de fungos do gênero Fusarium foram encontradas em sementes armazenadas com graus de umidade de 43% e 37% e mantidas em temperatura de 10 ºC

Produção de inseticida biológico com Bacillus thuringiensis.

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Bacillus thuringiensis production using cassava liquid waste (manipueira) as a fermentation substrate.

In developing countries the search for inexpensive substrates to grow useful microorganisms is a desirable way to get new and safe products to protect man against insect pest losses. Bacillus thuringiensis is an entomopathogenic bacteria, which by fermentation produces endo- or exotoxins to be used against Lepidoptera or Diptera, resp. These are insect pests of economic importance in developing countries, mainly in Brazil, where 60% losses in agriculture are caused by this type of pest. Our research group has been working with B. thuringiensis since 1970; and many papers have been published on the processes, culture media composition and available substrates, culture and operational conditions, equipment and so on. Many residues and waste waters were tried forthe fermentation culture medium. This paper reports the possibility of using manipueira, a residual waste water from cassava processing as a substrate to produce B. thuringiensis by fermentation. The culture medium was composed of 75% manipueira & 25% water. Operational conditions considered agitation and aeration rate, as well as initial pH and optimum growing temperature. Microbial growth and sporulation behavior were accomplished by optical density determination, pH variation and sugar consumption. Results are promising